<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            width: 100px;
            height: 200px;
            background: red;
            transition: all 2s linear 1s;
            /* 
            all 所有属性
            2s动画时间
            linear 匀速 
            1s 延迟
            
            除了display：none/block
            */
        }
       
        div:hover {
            height: 400px;
           width: 200px;
           background: yellow;
        }
    </style>
</head>

<body>
    <div></div>
</body>

</html>